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367 lines
12 KiB
367 lines
12 KiB
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/* |
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=============================================================================== |
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This C source fragment is part of the SoftFloat IEC/IEEE Floating-point |
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Arithmetic Package, Release 2. |
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Written by John R. Hauser. This work was made possible in part by the |
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International Computer Science Institute, located at Suite 600, 1947 Center |
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Street, Berkeley, California 94704. Funding was partially provided by the |
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National Science Foundation under grant MIP-9311980. The original version |
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of this code was written as part of a project to build a fixed-point vector |
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processor in collaboration with the University of California at Berkeley, |
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overseen by Profs. Nelson Morgan and John Wawrzynek. More information |
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is available through the Web page |
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http://www.jhauser.us/arithmetic/SoftFloat-2b/SoftFloat-source.txt |
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THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort |
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has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT |
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TIMES RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO |
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PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY |
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AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE. |
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Derivative works are acceptable, even for commercial purposes, so long as |
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(1) they include prominent notice that the work is derivative, and (2) they |
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include prominent notice akin to these three paragraphs for those parts of |
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this code that are retained. |
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=============================================================================== |
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*/ |
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/* |
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------------------------------------------------------------------------------- |
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Underflow tininess-detection mode, statically initialized to default value. |
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(The declaration in `softfloat.h' must match the `int8' type here.) |
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------------------------------------------------------------------------------- |
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*/ |
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int8 float_detect_tininess = float_tininess_after_rounding; |
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/* |
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------------------------------------------------------------------------------- |
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Raises the exceptions specified by `flags'. Floating-point traps can be |
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defined here if desired. It is currently not possible for such a trap to |
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substitute a result value. If traps are not implemented, this routine |
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should be simply `float_exception_flags |= flags;'. |
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ScottB: November 4, 1998 |
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Moved this function out of softfloat-specialize into fpmodule.c. |
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This effectively isolates all the changes required for integrating with the |
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Linux kernel into fpmodule.c. Porting to NetBSD should only require modifying |
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fpmodule.c to integrate with the NetBSD kernel (I hope!). |
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------------------------------------------------------------------------------- |
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void float_raise( int8 flags ) |
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{ |
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float_exception_flags |= flags; |
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} |
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*/ |
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/* |
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------------------------------------------------------------------------------- |
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Internal canonical NaN format. |
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------------------------------------------------------------------------------- |
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*/ |
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typedef struct { |
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flag sign; |
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bits64 high, low; |
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} commonNaNT; |
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/* |
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------------------------------------------------------------------------------- |
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The pattern for a default generated single-precision NaN. |
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------------------------------------------------------------------------------- |
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*/ |
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#define float32_default_nan 0xFFFFFFFF |
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/* |
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------------------------------------------------------------------------------- |
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Returns 1 if the single-precision floating-point value `a' is a NaN; |
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otherwise returns 0. |
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------------------------------------------------------------------------------- |
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*/ |
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flag float32_is_nan( float32 a ) |
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{ |
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return ( 0xFF000000 < (bits32) ( a<<1 ) ); |
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} |
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/* |
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------------------------------------------------------------------------------- |
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Returns 1 if the single-precision floating-point value `a' is a signaling |
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NaN; otherwise returns 0. |
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------------------------------------------------------------------------------- |
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*/ |
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flag float32_is_signaling_nan( float32 a ) |
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{ |
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return ( ( ( a>>22 ) & 0x1FF ) == 0x1FE ) && ( a & 0x003FFFFF ); |
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} |
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/* |
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------------------------------------------------------------------------------- |
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Returns the result of converting the single-precision floating-point NaN |
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`a' to the canonical NaN format. If `a' is a signaling NaN, the invalid |
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exception is raised. |
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------------------------------------------------------------------------------- |
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*/ |
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static commonNaNT float32ToCommonNaN( float32 a ) |
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{ |
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commonNaNT z; |
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if ( float32_is_signaling_nan( a ) ) float_raise( float_flag_invalid ); |
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z.sign = a>>31; |
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z.low = 0; |
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z.high = ( (bits64) a )<<41; |
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return z; |
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} |
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/* |
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------------------------------------------------------------------------------- |
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Returns the result of converting the canonical NaN `a' to the single- |
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precision floating-point format. |
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------------------------------------------------------------------------------- |
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*/ |
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static float32 commonNaNToFloat32( commonNaNT a ) |
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{ |
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return ( ( (bits32) a.sign )<<31 ) | 0x7FC00000 | ( a.high>>41 ); |
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} |
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/* |
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------------------------------------------------------------------------------- |
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Takes two single-precision floating-point values `a' and `b', one of which |
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is a NaN, and returns the appropriate NaN result. If either `a' or `b' is a |
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signaling NaN, the invalid exception is raised. |
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------------------------------------------------------------------------------- |
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*/ |
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static float32 propagateFloat32NaN( float32 a, float32 b ) |
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{ |
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flag aIsNaN, aIsSignalingNaN, bIsNaN, bIsSignalingNaN; |
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aIsNaN = float32_is_nan( a ); |
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aIsSignalingNaN = float32_is_signaling_nan( a ); |
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bIsNaN = float32_is_nan( b ); |
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bIsSignalingNaN = float32_is_signaling_nan( b ); |
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a |= 0x00400000; |
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b |= 0x00400000; |
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if ( aIsSignalingNaN | bIsSignalingNaN ) float_raise( float_flag_invalid ); |
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if ( aIsNaN ) { |
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return ( aIsSignalingNaN & bIsNaN ) ? b : a; |
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} |
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else { |
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return b; |
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} |
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} |
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/* |
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------------------------------------------------------------------------------- |
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The pattern for a default generated double-precision NaN. |
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------------------------------------------------------------------------------- |
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*/ |
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#define float64_default_nan LIT64( 0xFFFFFFFFFFFFFFFF ) |
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/* |
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------------------------------------------------------------------------------- |
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Returns 1 if the double-precision floating-point value `a' is a NaN; |
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otherwise returns 0. |
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------------------------------------------------------------------------------- |
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*/ |
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flag float64_is_nan( float64 a ) |
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{ |
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return ( LIT64( 0xFFE0000000000000 ) < (bits64) ( a<<1 ) ); |
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} |
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/* |
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------------------------------------------------------------------------------- |
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Returns 1 if the double-precision floating-point value `a' is a signaling |
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NaN; otherwise returns 0. |
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------------------------------------------------------------------------------- |
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*/ |
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flag float64_is_signaling_nan( float64 a ) |
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{ |
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return |
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( ( ( a>>51 ) & 0xFFF ) == 0xFFE ) |
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&& ( a & LIT64( 0x0007FFFFFFFFFFFF ) ); |
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} |
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/* |
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------------------------------------------------------------------------------- |
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Returns the result of converting the double-precision floating-point NaN |
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`a' to the canonical NaN format. If `a' is a signaling NaN, the invalid |
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exception is raised. |
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------------------------------------------------------------------------------- |
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*/ |
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static commonNaNT float64ToCommonNaN( float64 a ) |
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{ |
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commonNaNT z; |
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if ( float64_is_signaling_nan( a ) ) float_raise( float_flag_invalid ); |
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z.sign = a>>63; |
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z.low = 0; |
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z.high = a<<12; |
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return z; |
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} |
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/* |
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------------------------------------------------------------------------------- |
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Returns the result of converting the canonical NaN `a' to the double- |
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precision floating-point format. |
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------------------------------------------------------------------------------- |
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*/ |
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static float64 commonNaNToFloat64( commonNaNT a ) |
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{ |
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return |
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( ( (bits64) a.sign )<<63 ) |
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| LIT64( 0x7FF8000000000000 ) |
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| ( a.high>>12 ); |
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} |
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/* |
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------------------------------------------------------------------------------- |
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Takes two double-precision floating-point values `a' and `b', one of which |
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is a NaN, and returns the appropriate NaN result. If either `a' or `b' is a |
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signaling NaN, the invalid exception is raised. |
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------------------------------------------------------------------------------- |
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*/ |
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static float64 propagateFloat64NaN( float64 a, float64 b ) |
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{ |
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flag aIsNaN, aIsSignalingNaN, bIsNaN, bIsSignalingNaN; |
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aIsNaN = float64_is_nan( a ); |
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aIsSignalingNaN = float64_is_signaling_nan( a ); |
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bIsNaN = float64_is_nan( b ); |
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bIsSignalingNaN = float64_is_signaling_nan( b ); |
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a |= LIT64( 0x0008000000000000 ); |
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b |= LIT64( 0x0008000000000000 ); |
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if ( aIsSignalingNaN | bIsSignalingNaN ) float_raise( float_flag_invalid ); |
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if ( aIsNaN ) { |
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return ( aIsSignalingNaN & bIsNaN ) ? b : a; |
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} |
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else { |
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return b; |
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} |
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} |
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#ifdef FLOATX80 |
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/* |
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------------------------------------------------------------------------------- |
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The pattern for a default generated extended double-precision NaN. The |
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`high' and `low' values hold the most- and least-significant bits, |
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respectively. |
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------------------------------------------------------------------------------- |
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*/ |
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#define floatx80_default_nan_high 0xFFFF |
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#define floatx80_default_nan_low LIT64( 0xFFFFFFFFFFFFFFFF ) |
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/* |
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------------------------------------------------------------------------------- |
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Returns 1 if the extended double-precision floating-point value `a' is a |
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NaN; otherwise returns 0. |
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------------------------------------------------------------------------------- |
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*/ |
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flag floatx80_is_nan( floatx80 a ) |
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{ |
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return ( ( a.high & 0x7FFF ) == 0x7FFF ) && (bits64) ( a.low<<1 ); |
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} |
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/* |
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------------------------------------------------------------------------------- |
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Returns 1 if the extended double-precision floating-point value `a' is a |
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signaling NaN; otherwise returns 0. |
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------------------------------------------------------------------------------- |
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*/ |
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flag floatx80_is_signaling_nan( floatx80 a ) |
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{ |
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//register int lr; |
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bits64 aLow; |
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//__asm__("mov %0, lr" : : "g" (lr)); |
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//fp_printk("floatx80_is_signalling_nan() called from 0x%08x\n",lr); |
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aLow = a.low & ~ LIT64( 0x4000000000000000 ); |
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return |
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( ( a.high & 0x7FFF ) == 0x7FFF ) |
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&& (bits64) ( aLow<<1 ) |
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&& ( a.low == aLow ); |
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} |
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/* |
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------------------------------------------------------------------------------- |
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Returns the result of converting the extended double-precision floating- |
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point NaN `a' to the canonical NaN format. If `a' is a signaling NaN, the |
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invalid exception is raised. |
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------------------------------------------------------------------------------- |
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*/ |
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static commonNaNT floatx80ToCommonNaN( floatx80 a ) |
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{ |
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commonNaNT z; |
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if ( floatx80_is_signaling_nan( a ) ) float_raise( float_flag_invalid ); |
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z.sign = a.high>>15; |
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z.low = 0; |
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z.high = a.low<<1; |
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return z; |
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} |
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/* |
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------------------------------------------------------------------------------- |
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Returns the result of converting the canonical NaN `a' to the extended |
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double-precision floating-point format. |
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------------------------------------------------------------------------------- |
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*/ |
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static floatx80 commonNaNToFloatx80( commonNaNT a ) |
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{ |
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floatx80 z; |
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z.low = LIT64( 0xC000000000000000 ) | ( a.high>>1 ); |
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z.high = ( ( (bits16) a.sign )<<15 ) | 0x7FFF; |
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z.__padding = 0; |
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return z; |
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} |
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/* |
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------------------------------------------------------------------------------- |
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Takes two extended double-precision floating-point values `a' and `b', one |
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of which is a NaN, and returns the appropriate NaN result. If either `a' or |
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`b' is a signaling NaN, the invalid exception is raised. |
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------------------------------------------------------------------------------- |
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*/ |
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static floatx80 propagateFloatx80NaN( floatx80 a, floatx80 b ) |
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{ |
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flag aIsNaN, aIsSignalingNaN, bIsNaN, bIsSignalingNaN; |
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aIsNaN = floatx80_is_nan( a ); |
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aIsSignalingNaN = floatx80_is_signaling_nan( a ); |
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bIsNaN = floatx80_is_nan( b ); |
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bIsSignalingNaN = floatx80_is_signaling_nan( b ); |
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a.low |= LIT64( 0xC000000000000000 ); |
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b.low |= LIT64( 0xC000000000000000 ); |
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if ( aIsSignalingNaN | bIsSignalingNaN ) float_raise( float_flag_invalid ); |
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if ( aIsNaN ) { |
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return ( aIsSignalingNaN & bIsNaN ) ? b : a; |
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} |
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else { |
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return b; |
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} |
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} |
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#endif
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